Rolls of light sensitive web material (such as photographic paper and film) require light-tight packaging so that such rolls are not exposed to white or room light whereby the light sensitive characteristics of the rolls would be adversely effected.
A known method of light shielding an unexposed roll of photographic film is shown in FIG. 1. As shown, a spool 10 includes a core 12 and a pair of flanges 14,16 disposed at opposite ends of core 12. Web material W is wound between the flanges 14, 16. A light-shielding opaque member 18 is attached to web material W, for example by means of an adhesive tape 19, and wound about the web material W to shield the web material W from light.
With the light-shielding member wound about the film roll, a variety of securing or sealing means may be employed for sealing closed the light-shielding member of an unexposed photographic film roll. U.S. Pat. No. 5,790,912 (Myers) commonly assigned and incorporated herewith by reference, relates to a tear-out region having an adhesive which bonds to an underlying convolution of the light-shielding member. Other means for sealing closed a light-shielding member of an unexposed photographic film roll are disclosed in U.S. Pat. No. 2,188,779 (Roehrl), U.S. Pat. No. 3,022,170 (Flinchbaugh), and U.S. Pat. No. 3,986,879 (Klinkammer).
After the photographic film roll has been exposed, for example, using a camera (not shown), the exposed photographic film may be rewound onto the spool. Alternatively, the exposed film may be wound onto another, different spool. If wound onto another spool, the light-tight packaging may include a light-shielding member arranged to light shield the wound roll of photographic film.
U.S. Pat. No. 1,454,812 (Jones), U.S. Pat. No. 1,454,813 (Jones), and U.S. Pat. No. 1,454,814 (Jones), all commonly assigned and incorporated herewith by reference, relate to a roll package having such an arrangement. As shown in FIG. 2, a roll package includes a light-shielding leader 20 disposed at one end of the web material W, and a light-shielding trailer 22 disposed at the other end of the web material W, with the light-shielding trailer 22 being engaged to spool 10, for example by a slot (not shown). Accordingly, when the unexposed web material W is wound about spool 10 between end flanges 14,16, trailer 22 is first wound, then the web material W is wound, with leader 20 being wound about the web material W. After exposure, the exposed web material W is wound onto another spool such that leader 20 is first wound about the spool, then the exposed web material W is wound, with trailer 22 being wound about the exposed web material W. Such a film roll configuration (i.e., trailer/web/leader) has been generally referred to as 220 format film roll.
Another film roll adapted for winding of exposed web material W onto another spool after exposure is illustrated in FIG. 3, and generally referred to as a 120 format film roll. As illustrated, a light-shielding backing material 24 is disposed on one side of the web material W along the entire length of the web material W, with a length of light-shielding backing material 24 being greater than the length of the web material W. The backing material may extend beyond the web material W at both ends. Accordingly, when the web material W and light-shielding backing material 24 are wound onto the spool 10 between the flanges 14, 16, the wound convolutions alternate between the web material W and the light-shielding backing material 24.
A variety of securing or sealing means may be employed for securing or sealing closed the light-shielding member of an exposed photographic film roll.
U.S. Pat. No. 1,991,442 (Barenyi) discloses a strip of gummed paper attached to the end of a protective backing strip wherein the gummed strip is used to fix the exposed film in position on a film receiving spool. One portion of the gummed strip is attached to the backing strip and another portion lies loose with its outer portion on the backing strip. The gummed strip is exposed by tearing off an end of the backing strip.
U.S. Pat. No. 3,647,465 (Shamay) discloses a paper wrapper strip attached to an outer end of a masking strip with the legend EXPOSED which is displayed when the exposed film is wound on the spool.
Some known photographic film rolls include a light-shielding member 28 having a tongue 30 and a gummed strip 32 as illustrated in FIG. 4. A first portion 34 of gummed strip 32 is attached to light-shielding member 28 and a second portion 36 is not attached to light-shielding member 28. Second portion 36 comprises a moisture-activated adhesive on its inner side. To secure the photographic film roll, light-shielding member 28 is wound about spool 10 and tongue 30 is folded back under itself, for example along transverse line 38. Second portion 36 is round about the roll and secured to light-shielding member 28 after the adhesive is moisture activated. The resulting wound roll is illustrated in FIG. 5.
The strips of these references are generally referred to as an "after exposure label" or "exposure label" since the strip is applied to the roll film after exposure to support the film in a roll shape for transport to a developer. An optional legend "EXPOSED" on the strip indicates to a user that the roll film has been exposed.
While such after exposure labels may have achieved certain degrees of success in their particular application, currently, the after exposure labels are activated by moisture or application of a liquid, for example by licking. Unfortunately, the flavoring of such "lick-n-stick" labels has been considered to be offensive by users.
Accordingly, a need continues to exist for a means for sealing a roll of exposed photographic film which does not require a liquid or moisture for activation, provides secure closure of the roll, and is not photoactive. Further, the means for sealing must not adversely affect the photosensitive characteristics of the film, such as impressions resulting from discontinuous edges or thick material areas.